Which oil for a 1991 Mercruiser 4.3LX?

fishingdan

Lieutenant Junior Grade
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Feb 12, 2005
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Anyone know what weight oil should be used in one of these engines?

Thanks,
Dan
 

JustJason

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Re: Which oil for a 1991 Mercruiser 4.3LX?

yep.... the recommended weight is 25w-40...... as per mercruiser.
although.... any good name quality oil is fine. 10-30 10-40 20-40... it's all good. just keep an eye on the level.
 

mthieme

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Re: Which oil for a 1991 Mercruiser 4.3LX?

I run Wally World 30HD in my (OMC) 4.3...motor has been in the boat 20 years, has thousands of hours on it and never been apart...still running fine.
 

mthieme

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Re: Which oil for a 1991 Mercruiser 4.3LX?

I run Wally World 30HD in my (OMC) 4.3...motor has been in the boat 20 years, has thousands of hours on it and never been apart...still running fine.
see sig pic taken this summer
 

Chris1956

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Mar 25, 2004
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Re: Which oil for a 1991 Mercruiser 4.3LX?

Dan, MerCruiser has always recommended Automotive straight weight oil (SAE 30 or SAE 40) or their own multiweight oil (Quicksilver 25W-40). They have never recommended automotive multi weight oil. Lots of folks claim to use it w/o a problem, however I would never take that chance.

I always used the Quicksilver 25W-40 oil.
 

achris

More fish than mountain goat
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Re: Which oil for a 1991 Mercruiser 4.3LX?

And I use 15W-40 Diesel engine oil.
 

Fishermark

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Re: Which oil for a 1991 Mercruiser 4.3LX?

From Mercruiser:

faqs_temp.gif
 

180shabah

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Re: Which oil for a 1991 Mercruiser 4.3LX?

shocked003.gif
OIL THREAD!!!!

Search oil - you can read for days
 
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